1. Field of the Invention
The invention concerns a displacement unit, particularly for a roller balance or a displacement joint of a universal shaft with a tubular exterior part on the interior surface of which outer paths are provided at least in sections, with an inner part that is displaceable in the outer part in axial direction, on whose exterior surface interior running paths are provided at least in sections, and with balls for the transmission of torque that are guided in a cage that are respectively located in outer paths and inner paths that are associated with each other in pairs, whereby the outer part and/or the inner part is provided with cage guide paths between at least some of the exterior paths or interior paths for axial guiding of the cage. Further, the invention concerns a universal shaft with a displacement unit of this type.
2. Description of Related Art
From DE 102 37 169 A1, a displacement joint is known of the type mentioned at the beginning. The cage guide paths are thereby designed either as centering slots in an outer part between two ball paths respectively or in an inner part as centering slot between the ball paths. Alternatively, it is also possible that the cage is designed as folding cage that has a wavy profile in cross section. In this process, the cage can project into the ball paths with cage guide pins in sections, so that the cage is guided twist-safe and displaceable in axial direction on the inner race.
To avoid distortion or tension when hardening or similar subsequent treatment of the displacement unit, it is preferred to keep the quantity of cage guide paths and run paths pairs identical, whereby the cage guide paths and the paths pairs are located evenly distributed around the circumference.
In DE 199 52 245 A1, a displacement unit that is designed as a roller balance was suggested in which the quantity of the outer paths corresponds to double or triple the quantity of the inner paths. This is said to also avoid deformations due to hardening. In these arrangements, however, the quantity of the pairs of paths in which balls are located for transmission of torque is limited.